a method and algorithm for reconstructing the three-dimensional surface of tree stems using laser scanner,is presented.Firstly,laser scanner delivers a dense cloud of points on a tree.Secondly,this raw point data are filtered for deriving a sequence of segments of tree stem.Finally,these segments of stem are put together and fit of an integrity tree 's stem model.The model gotten by this method is made up of a series of successive cylinders that overlap in space.The use of resulting 3D reconstruction of tree stem in respect to diameter in breast height,as well as taper and lean assessment of standing trees,is described.A good effect is gotten using this method in practice.